ML20247H360
| ML20247H360 | |
| Person / Time | |
|---|---|
| Site: | 05200002, 05000470 |
| Issue date: | 03/30/1989 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | |
| Shared Package | |
| ML20247G537 | List:
|
| References | |
| NUDOCS 8904040445 | |
| Download: ML20247H360 (6) | |
Text
.
CESSAR !!!nney,.
APPENDIX 11A CORE RESIDENCE TIMES I
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8904040445 890330 PDR ADOCK 05000470-K PDR
CESSAR 8!nincano,.
(Sheet 1 of 1) o EFFECTIVE PAGE LISTING APPENDIX 11A Table of Contents P_ age Amendment i
Text Pace Amendment 11A-1 11A-2 11A-3 O
O Amendment E December 30, 1988
CESSAR !!nifico =
TABLE OF CONTENTS
-APPENDIX 11A Section Subiect Pace No.
1.0 DERIVATION OF CORE RESIDENCE 11A-1 TIMES j
i
[~
CESSAR !! Sinc m.,
O 1.0 DERIVATION OF CORE RESIDENCE TIMES The derivation of the core residence times for circulating crud as shown in Section 11.1.2 is as follows:
A.
Circulating Crud:
The number of radioactive atoms (N ) in the crud film on f
in-core surfaces at any time is:
dN g *Ed-1"f (11A-1) i dt Solving for N yields the following:
g
^I #*8) atoms /g (11A-2)
N (1 - e
=
g i
Where:
I 4
is the activation rate for each isotope i f
(d/g-sec),
is th decay constant for each isotope A
(secs p),
f and t
is the desired core residence time (seconds).
res The number of radioactive atoms (N ) released to the reactor c
coolant at any time is:
[DN=N
[ER] A
("+0+A i) N atoms /sec
~
f c
c Solving for N yields the following:
c N (ER) A "I" + 0 + A 1) t f
c N
(1 - e
)
(11A-3) o" (a + B + A.)
1 2
Where:
ER is the erosion rate (g/cm -sec),
A is the core surface area (cm ),
c is the plateout rate (secs-1),
o a
llA-1
1 CESSAR E!i#icari:u I
Oi p
is the purification cleanup rate (secs-1),
and A
is the decay constant (secs-1),
y Total amount of crud (M ) released to the reactor coolant any time is:
dM
[ER) A
- (
+
)M (11A~4)
=
T c
dt where M in ludes both radioactive and nonradioactive material.
c Solving for M yields:
c l
)t) grams (11A-5)
- (a +
l M
(1 ~
- c"
)
Where:
ER is the erosion rate (g/cm -sec),
1 A
is the total system area (cm ),
T
~
is the plateout rate (secs ~ ),
and a
p is the purification cleanup rate (secs ~1).
The activity (A )
of the crud released to the reactor g
coolant is:
A N fC dps per gram of crud in reactor (11A-6)
A1=M c
coolant substituting the values of N
and M
into the above expression and assuming 1.
is shall when compared to a and l
p, the activity of the crud is as follows:
A
~ i res)
(0.06) dpm/mb-crud c
(1 -e Ag=If lu-7) where 0.06 is a constant changing dps/g-crud to dpm/mg-crud.
This activity (A.
is also assumed to be the activity of the crud which plated) out on out-of-core surfaces.
Solving equation (11A-7) for t yields quation (1)
(See es Section 11.1.2).
CESSAR ninneuio B.
Denosited Crud The activity (A ) of the deposited crud is 3
g g = Z d (1:- e res).0.06 (11A-8)
N A
=A y
Solving equation (11A-8) for't yields. equation (2). (See res Section 11.1.2) 1 i